JP5992197B2 - LED lighting device and display device including the same - Google Patents

Description

  The present invention relates to an LED lighting device that emits light with an alternating voltage and a display device including the same.

  There is known a blinker light (display device) that is installed at a branch point of a road or the like and alerts the driver of a vehicle such as a median strip by alternately blinking two incandescent light bulbs.

  FIG. 7 is a block diagram showing a configuration of a conventional blinker light. As shown in FIG. 7, the blinker light includes a control panel 20 that controls lighting of the incandescent bulbs 100 and 100 according to the amount of ambient light. The control panel 20 alternately supplies the first AC voltage VAC1 (effective value 100V) obtained by converting the input AC voltage VACin (effective value 200V) from the AC power supply E to the two incandescent lamps 100 and 100 in the daytime. The control panel 20 alternately supplies a second AC voltage VAC2 (effective value 60V) obtained by converting the input AC voltage VACin to the two incandescent lamps 100 and 100 at night. At night, even if the brightness of the incandescent bulbs 100, 100 is lowered, blinking is easy to recognize, so the voltage is lowered to reduce power consumption.

  Incidentally, in recent years, attention has been focused on LED bulbs (hereinafter referred to as LED lighting devices) having characteristics of low power consumption, long life, easy maintenance, and high reliability compared to incandescent bulbs.

  For example, the LED lighting device 10X having the configuration shown in FIG. 8 can be replaced with an incandescent lamp by using the existing wiring for the incandescent lamp in a lighting fixture or the like as it is. This LED lighting device 10X performs full-wave rectification on the supplied AC voltage with a rectifying element (bridge diode) B1 and applies the rectified rectified voltage to the LED element 110, thereby lighting the LED element 110. The LED element 110 includes a plurality of LEDs (LED1 to LEDN) connected in series. At this time, the current control unit 130 controls the current flowing through the LED element 110 to a constant current. As a device similar to the LED lighting device 10X, for example, a device described in Patent Document 1 is known.

  Even in the blinker light, if the incandescent lamp 100 is replaced with the LED lighting device 10X using the existing control panel 20 installed at a branch point of the road as it is, the above-described excellent characteristics can be easily achieved at low cost. Can be obtained.

JP 2004-093657 A

  However, in the conventional LED lighting device 10X, due to the electrical characteristics of the LEDs, a rectified voltage equal to or higher than the LED forward voltage Vf × N is required to light the N LEDs. For example, in the LED lighting device 10X designed for an AC voltage having an effective value of 100V, if N = 34 and Vf = 3V, a rectified voltage of 102V or more is required. Therefore, when the incandescent bulb of the blinker light is replaced with such an LED lighting device 10X, there is a problem that the LED lighting device 10X does not light at night when the second AC voltage VAC2 having an effective value of 60V is supplied.

  Then, an object of this invention is to provide the LED lighting device which can be lighted with two types of alternating voltage from which an effective value differs, and a display apparatus provided with the same.

An LED lighting device according to an embodiment according to one aspect of the present invention,
When the amount of ambient light is greater than or equal to a predetermined reference amount of light, a first AC voltage is output. When the amount of light is lower than the reference amount of light, the second effective value is lower than the first AC voltage. An LED lighting device to which the first AC voltage or the second AC voltage is supplied from a lighting control unit that outputs an AC voltage,
A rectifying element that rectifies the first AC voltage or the second AC voltage and outputs a rectified voltage between the first terminal and the second terminal;
A first LED element having one end connected to the first terminal;
A second LED element having one end connected to the other end of the first LED element;
A current control unit that is connected between the other end of the second LED element and the second terminal and controls a current flowing through the first LED element or the second LED element;
A short-circuit control unit that short-circuits both ends of the first LED element or the second LED element when the rectified voltage is less than a predetermined short-circuit voltage,
The maximum value of the short-circuit voltage and the second AC voltage is equal to or lower than the first voltage required for both the first LED element and the second LED element to be lit, and the first When one of the second LED element and the second LED element is short-circuited, the other is higher than the second voltage required for lighting.

In the LED lighting device,
The short circuit voltage may be higher than a maximum value of the second AC voltage.

In the LED lighting device,
The short-circuit controller is
A shorting switch that is switched on or off and shorts both ends of the second LED element when on;
A first voltage detecting element having one end connected to the first terminal and conducting when the rectified voltage is equal to or higher than the short-circuit voltage;
A first resistor having one end connected to the first terminal;
A control terminal is connected to the other end of the first voltage detection element, one end is connected to the other end of the first resistor, the other end is connected to the second terminal, and the first voltage detection element is conductive. A first switching element that is turned on when
The short-circuit switch may be controlled to be turned on when the voltage at the other end of the first resistor is at a high level, and may be controlled to be turned off when the voltage is at a low level.

In the LED lighting device,
The short-circuit switch is an N-type MOS transistor,
The drain of the N-type MOS transistor is connected to a connection point between the other end of the first LED element and one end of the second LED element, and the source of the N-type MOS transistor is the other LED element. Connected to the connection point between the end and the current control unit,
The short-circuit control unit may include a voltage limiting element that limits a voltage between a gate and a source of the N-type MOS transistor.

In the LED lighting device,
The short-circuit control unit may include a current limiting element that restricts current from flowing from a connection point between the other end of the second LED element and the current control unit to the short-circuit control unit.

In the LED lighting device,
The first voltage detecting element is a Zener diode;
The short-circuit control unit may include a second resistor connected between a control terminal of the first switching element and the second terminal.

In the LED lighting device,
A resistance switching unit that includes a third resistor and a fourth resistor, and switches a resistance between the first terminal and the second terminal based on the supplied rectified voltage;
The lighting control unit supplies the first AC voltage or the second AC voltage to the rectifying element via a switch unit that is switched on or off and has a resistance component when off,
The resistance switching unit connects the third resistor between the first terminal and the second terminal when the rectified voltage is less than a determination voltage, and thereby connects the third resistor to the switch unit via the rectifying element. When the rectified voltage is equal to or higher than the determination voltage, the fourth resistor having a higher resistance than the third resistor is provided between the first terminal and the second terminal instead of the third resistor. Thus, the fourth resistor may be electrically connected to the switch unit via the rectifying element.

In the LED lighting device,
When the switch unit is off, the rectified voltage may be stepped down below the determination voltage by the resistance component of the switch unit and the third resistor.

In the LED lighting device,
The third resistor may have a lower resistance than the resistance component of the switch unit.

In the LED lighting device,
The current controller is
A current control transistor having one end connected to the other end of the second LED element;
A fifth resistor connected between the other end of the current control transistor and the second terminal;
A voltage control unit that controls a voltage at a control terminal of the current control transistor so that a voltage at the other end of the current control transistor is constant.

In the LED lighting device,
The voltage controller is
A second voltage detecting element having one end connected to the first terminal and conducting when the rectified voltage is equal to or higher than the determination voltage; and the determination voltage is less than the second voltage;
A sixth resistor having one end connected to the other end of the second voltage detection element;
A seventh resistor connected between the other end of the sixth resistor and the second terminal;
A cathode is connected to the other end of the sixth resistor and a control terminal of the current control element, an anode is connected to the second terminal, and a reference voltage based on the voltage at the other end of the current control transistor is supplied to a reference terminal. A shunt regulator that decreases the cathode voltage when the reference voltage increases and increases the cathode voltage when the reference voltage decreases.

In the LED lighting device,
The resistance switching unit
A control terminal is connected to the other end of the second voltage detection element of the voltage control unit, and one end and the other end are connected between the fourth resistor and the second terminal, and the second voltage detection element A second switching element that is turned on when is conducted;
A control terminal is connected to the one end of the second switching element, one end and the other end are connected between the third resistor and the second terminal, and the second switching element is turned off when the second switching element is turned on. 3 switching elements.

In the LED lighting device,
Each of the first LED element and the second LED element may be composed of a plurality of LEDs connected in series.

A display device according to an embodiment of one aspect of the present invention includes:
A first LED lighting device;
A second LED lighting device;
When the amount of ambient light is greater than or equal to a predetermined reference amount of light, the first alternating voltage is alternately supplied to the first and second LED lighting devices, while when the amount of light is lower than the reference amount of light, A lighting control unit that alternately supplies a second AC voltage having an effective value lower than that of the first AC voltage to the first and second LED lighting devices.

  According to the LED lighting device of the present invention, when the rectified voltage is less than the short-circuit voltage, the short-circuit control unit short-circuits one of the first LED element and the second LED element connected in series. . The maximum value of the absolute value of the short-circuit voltage and the second AC voltage is equal to or lower than the first voltage required for both the first LED element and the second LED element to be lit, and the first LED Of the element and the second LED element, the one that is not short-circuited is higher than the second voltage required for lighting. Thereby, even when the 2nd alternating voltage whose effective value is lower than a 1st alternating voltage is supplied, the number of LED elements can be reduced and it can be made to light.

  Furthermore, when the first AC voltage is supplied, the LED element can be lit even in a period in which the rectified voltage drops below the first voltage according to the period of the first AC voltage, so that the conduction width is widened. it can. That is, the brightness is increased and the visibility is improved.

1 is a block diagram illustrating a schematic configuration of a blinker light according to Example 1. FIG. 1 is a circuit diagram of an LED lighting device according to Example 1. FIG. It is a wave form diagram when the 1st alternating voltage of the LED lighting device which concerns on Example 1 is supplied. It is a wave form diagram when the 2nd alternating voltage of the LED lighting device which concerns on Example 1 is supplied. 6 is a block diagram showing a schematic configuration of a blinker light according to Example 2. FIG. It is a circuit diagram of the LED lighting device which concerns on Example 2. FIG. It is a block diagram which shows the schematic structure of the conventional blinker light. It is a circuit diagram of the conventional LED lighting device.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating a schematic configuration of a blinker light (display device) according to the first embodiment. As shown in FIG. 1, the blinker light includes first and second LED lighting devices (LED bulbs) 10 and 10, and a lighting control unit (control panel) 20.

  The lighting control unit 20 includes a voltage conversion unit 21 having an optical sensor (not shown) and two switches SW1 and SW1. The light sensor of the voltage converter 21 is arranged so as to receive light around the blinker light.

  The lighting controller 20 is supplied with the input AC voltage VACin from the AC power source E. For example, the effective value of the input AC voltage VACin is 200 V, and the frequency is 50 or 60 Hz.

  The lighting controller 20 uses the voltage converter 21 to convert the input AC voltage VACin into the first AC voltage VAC1 when the amount of ambient light is equal to or greater than a predetermined reference light amount (that is, in the daytime). The lighting control unit 20 alternately supplies the first AC voltage VAC1 to the first and second LED lighting devices 10 and 10 by alternately turning on the two switches SW1 and SW1. The effective value of the first AC voltage VAC1 is, for example, 100V. The time for which each switch SW1, SW1 is turned on is, for example, about 2 seconds.

  On the other hand, when the amount of ambient light is lower than the reference light amount (that is, at night), the lighting control unit 20 uses the input AC voltage VACin whose effective value is lower than that of the first AC voltage VAC1. 2 to AC voltage VAC2. The lighting control unit 20 alternately supplies the second AC voltage VAC2 to the first and second LED lighting devices 10 and 10 by alternately turning on the two switches SW1 and SW1. The effective value of the second AC voltage VAC2 is, for example, 60V.

  In this way, the first and second LED lighting devices 10 and 10 blink alternately. At night, even if the brightness of the first and second LED lighting devices 10 and 10 is decreased, blinking can be easily recognized, so the voltage is reduced to reduce power consumption.

  FIG. 2 is a circuit diagram of the LED lighting device 10 according to the first embodiment. The LED lighting device 10 includes a rectifying element B1, a first LED element 11-1, a second LED element 11-2, a current control unit 13, and a short-circuit control unit 14.

  The rectifying element B1 is a bridge diode composed of four diodes, and full-wave rectifies the first AC voltage VAC1 or the second AC voltage VAC2 supplied from the lighting control unit 20, and the first terminal T1 and The rectified voltage Vr is output from between the second terminals T2.

  The first LED element 11-1 has an anode (one end) connected to the first terminal T1. The second LED element 11-2 has an anode (one end) connected to the cathode (the other end) of the first LED element 11-1. In this embodiment, the first LED element 11-1 is composed of 19 LEDs (LED1 to LED19) connected in series, and the second LED element 11-2 is 15 LEDs connected in series. (LED20 to LED34).

  The current control unit 13 is connected between the cathode (the other end) of the second LED element 11-2 and the second terminal T2, and controls the current flowing through the first LED element 11-1.

  The short-circuit control unit 14 short-circuits both ends of the second LED element 11-2 when the rectified voltage Vr is less than a predetermined short-circuit voltage. The short-circuit voltage is equal to or lower than the first voltage required for both the first LED element 11-1 and the second LED element 11-2 to be lit, and the first LED element 11-1 and the second LED element 11-2 When one of the LED elements 11-2 is short-circuited, the other is higher than the second voltage necessary for lighting. The short circuit voltage is preferably higher than the maximum value of the second AC voltage VAC2. This is because it is preferable that both ends of the second LED element 11-2 are kept short-circuited when the second AC voltage VAC2 is supplied. The maximum value of the second AC voltage VAC2 is equal to or lower than the first voltage and higher than the second voltage.

  In the present embodiment, the current control unit 13 and the short circuit control unit 14 are configured as follows.

  The current control unit 13 includes an N-type MOS transistor (current control transistor) Q1, a resistor (fifth resistor) R1, and a voltage control unit 131.

  The N-type MOS transistor Q1 has a drain (one end) connected to the cathode of the second LED element 11-2. The resistor R1 is connected between the source (the other end) of the N-type MOS transistor Q1 and the second terminal T2.

  The voltage control unit 131 controls the voltage of the gate (control terminal) of the N-type MOS transistor Q1 so that the source voltage of the N-type MOS transistor Q1 becomes constant.

  The voltage control unit 131 includes a Zener diode (second voltage detection element) ZD1, a resistor (sixth resistor) R2, a resistor (seventh resistor) R3, a resistor R4, a resistor R5, a shunt regulator IC1, A capacitor C1 and a capacitor C2 are included.

  The Zener diode ZD1 is electrically connected when the cathode (one end) is connected to the first terminal T1 and the rectified voltage Vr is equal to or higher than the determination voltage. The determination voltage is the Zener voltage of the Zener diode ZD1 and is less than the second voltage.

  The resistor R2 has one end connected to the anode (the other end) of the Zener diode ZD1. The resistor R3 is connected between the other end of the resistor R2 and the second terminal T2.

  The shunt regulator IC1 has a cathode connected to the other end of the resistor R2 and the gate of the N-type MOS transistor Q1, and an anode connected to the second terminal T2. In the shunt regulator IC1, the reference voltage Vref based on the source voltage of the N-type MOS transistor Q1 is supplied to the reference terminal, the cathode voltage decreases when the reference voltage Vref increases, and the cathode voltage decreases when the reference voltage Vref decreases. To increase.

  The resistor R4 has one end connected to the source of the N-type MOS transistor Q1, and the other end connected to the reference terminal of the shunt regulator IC1. The resistor R5 is connected between the other end of the resistor R4 and the second terminal T2. That is, the resistor R4 and the resistor R5 divide the source voltage of the N-type MOS transistor Q1 to generate the reference voltage Vref.

  The capacitor C1 is connected between the gate of the N-type MOS transistor Q1 and the second terminal T2. The capacitor C2 is connected between the gate and source of the N-type MOS transistor Q1. These capacitors C1 and C2 are provided to prevent oscillation when the N-type MOS transistor Q1 operates at high speed.

  In this way, since the gate voltage of the N-type MOS transistor Q1 is controlled to be substantially constant, the current flowing through the first LED element 11-1 is controlled to be substantially constant.

  The short-circuit control unit 14 includes an N-type MOS transistor (short-circuit switch) Q2, a Zener diode (first voltage detection element) ZD2, a resistor R6, a resistor R7, a resistor (first resistor) R8, and a resistor (first resistor). 2 resistors) R9, an NPN transistor (first switching element) Q3, a Zener diode (voltage limiting element) ZD3, and a diode (current limiting element) D1.

  The drain of the N-type MOS transistor Q2 is connected to a connection point between the cathode of the first LED element 11-1 and the anode of the second LED element 11-2. The source of the N-type MOS transistor Q2 is connected to a connection point between the cathode of the second LED element 11-2 and the drain of the N-type MOS transistor Q1 via a diode D1. As a result, the N-type MOS transistor Q2 is switched on or off, and short-circuits both ends of the second LED element 11-2 when turned on.

  The Zener diode ZD2 has a cathode (one end) connected to the first terminal T1 via a resistor R6, and an anode (the other end) connected to the base (control terminal) of the NPN transistor Q3. The resistor R7 is connected between the cathode of the Zener diode ZD2 and the second terminal T2.

  The Zener diode ZD2 is set with a Zener voltage so as to be conductive when the rectified voltage Vr is equal to or higher than the short-circuit voltage.

  The resistor R8 has one end connected to the first terminal T1. In the NPN transistor Q3, a collector (one end) is connected to the other end of the resistor R8, and an emitter (the other end) is connected to the second terminal T2. As a result, the NPN transistor Q3 is turned on when the Zener diode ZD2 becomes conductive.

  The resistor R9 is connected between the base of the NPN transistor Q3 and the second terminal T2. The resistor R9 prevents the leakage current from flowing between the base and the emitter of the NPN transistor Q3 when a leakage current flows from the cathode to the anode of the Zener diode ZD2 and flows to the second terminal T2. This can prevent the NPN transistor Q3 from being turned on by the leakage current before the rectified voltage Vr becomes equal to or higher than the short-circuit voltage.

  The gate of the N-type MOS transistor Q2 is connected to the connection point between the collector of the NPN transistor Q3 and the resistor R8. As a result, the N-type MOS transistor Q2 is controlled to turn on when the voltage at the other end of the resistor R8 (that is, the voltage at the collector of the NPN transistor Q3) is high level, and is controlled to be off when the voltage is low level.

  The Zener diode ZD3 has a cathode connected to the gate of the N-type MOS transistor Q2, and an anode connected to the source. Thus, the Zener diode ZD3 limits the voltage between the gate and source of the N-type MOS transistor Q2 to the Zener voltage of the Zener diode ZD3.

  The diode D1 has an anode connected to the source of the N-type MOS transistor Q2, and a cathode connected to the cathode of the second LED element 11-2. Thereby, the diode D1 restricts the current from flowing from the connection point between the cathode of the second LED element 11-2 and the current control unit 13 to the short-circuit control unit 14.

  Next, the operation of the LED lighting device 10 will be described with reference to the waveform diagrams of FIGS.

  FIG. 3 is a waveform diagram of the LED lighting device 10 according to the first embodiment when the first AC voltage VAC1 is supplied. FIG. 3 shows the rectified voltage Vr and the current flowing through the first LED element 11-1.

  Since the rectified voltage Vr is less than the short-circuit voltage from time t1 to time t4 in FIG. 3, the Zener diode ZD2 is not conducted as described above, and the NPN transistor Q3 is off. As a result, the gate voltage of the N-type MOS transistor Q2 is substantially equal (that is, higher) than the voltage at the terminal T1, and the N-type MOS transistor Q2 is on. Therefore, the N-type MOS transistor Q2 short-circuits both ends of the second LED element 11-2 via the diode D1.

  When the rectified voltage Vr becomes equal to or higher than the determination voltage at time t2, the Zener diode ZD1 becomes conductive, and the voltage control unit 131 can control the gate voltage of the N-type MOS transistor Q1.

  Since only 19 LEDs (LED1 to LED19) constituting the first LED element 11-1 are connected to the current path between the first terminal T1 and the second terminal T2, rectification is performed at time t3. When the voltage Vr exceeds the second voltage (forward voltage Vf × 19), a current flows through the first LED element 11-1, and the first LED element 11-1 is lit.

  When the rectified voltage Vr becomes equal to or higher than the short-circuit voltage at time t4, the Zener diode ZD2 becomes conductive and the NPN transistor Q3 is turned on. As a result, the gate voltage of the N-type MOS transistor Q2 is lowered, and the N-type MOS transistor Q2 is turned off. That is, the N-type MOS transistor Q2 does not short-circuit both ends of the second LED element 11-2.

  Therefore, in the current path between the first terminal T1 and the second terminal T2, 34 LEDs (LED1 to LED34) constituting the first LED element 11-1 and the second LED element 11-2 are provided. Connected. In this embodiment, the short circuit voltage is substantially equal to the first voltage (forward voltage Vf × 34). Thereby, an electric current flows into the 1st LED element 11-1 and the 2nd LED element 11-2, and it lights.

  From time t5 to t8, the same operation as described above is performed. That is, in the period from time t3 to t4 and from t5 to t6, the first LED element 11-1 is lit and the second LED element 11-2 is not lit. In the period from time t4 to t5, the first LED element 11-1 is not lit. The LED element 11-1 and the second LED element 11-2 are lit.

  Note that the gate voltage of the N-type MOS transistor Q2 is lower than the drain voltage of the N-type MOS transistor Q1 while the N-type MOS transistor Q2 is off. Even in this case, the presence of the diode D1 prevents current from flowing from the connection point between the cathode of the second LED element 11-2 and the drain of the N-type MOS transistor Q1 to the NPN transistor Q3 via the Zener diode ZD2. Because it is restricted, there is no risk of malfunction or failure.

  FIG. 4 is a waveform diagram when the second AC voltage VAC2 of the LED lighting device 10 according to the first embodiment is supplied.

  In the case of FIG. 4, since the short circuit voltage is higher than the maximum value of the second AC voltage VAC2, the rectified voltage Vr is always less than the short circuit voltage. Therefore, the N-type MOS transistor Q2 always short-circuits both ends of the second LED element 11-2 via the diode D1. That is, only 19 LEDs (LED1 to LED19) constituting the first LED element 11-1 are connected to the current path between the first terminal T1 and the second terminal T2.

  Therefore, after the rectified voltage Vr increases after time t11 and becomes equal to or higher than the determination voltage at time t12, when the rectified voltage Vr exceeds the second voltage at time t13, a current flows through the first LED element 11-1. Thus, the first LED element 11-1 is lit.

  When the rectified voltage Vr becomes less than the second voltage at time t14, the first LED element 11-1 is turned off. That is, the first LED element 11-1 is turned on during the period from time t13 to t14, and is turned off during the other periods from time t11 to t13 and from time t14 to t16.

  As described above, according to the present embodiment, the short-circuit control unit 14 short-circuits the second LED element 11-2 when the rectified voltage Vr is less than the short-circuit voltage. The maximum value of the short-circuit voltage and the absolute value of the second AC voltage VAC2 is equal to or lower than the first voltage required for both the first LED element 11-1 and the second LED element 11-2 to light. And it is higher than the 2nd voltage required in order for the 1st LED element 11-1 to light. As a result, even when the second AC voltage VAC2 having an effective value lower than that of the first AC voltage VAC1 is supplied, the number of LED elements can be reduced to light the LED.

  Further, when the first AC voltage VAC1 is supplied, the first LED element 11-1 is lit even during a period in which the rectified voltage Vr decreases below the first voltage according to the cycle of the first AC voltage VAC1. Therefore, the conduction width can be widened. That is, in the blinker light, the daytime luminance is increased and the visibility is improved.

  In this way, by simply using the blinker light lighting control unit (control panel) 20 already installed at a road junction or the like, the incandescent light bulb can be replaced with the LED lighting device 10 to achieve low power consumption and long life. Therefore, it is possible to obtain the excellent characteristics of the LED, such as easy maintenance and high reliability.

  In addition, when the first AC voltage VAC1 is supplied, the first and second LED elements 11-1 and 11-2 have the same brightness as that of a conventional LED lighting device that does not include the short-circuit control unit 14. Since the flowing current can be reduced, power loss can be reduced, and the temperature rise can be suppressed by reducing the heat generation amount.

  In addition, the LED lighting device 10 can be realized without using high breakdown voltage and high power components.

  The second embodiment relates to an LED lighting device 10a applicable to a blinker light using a semiconductor relay SSR instead of the switch SW1.

  FIG. 5 is a block diagram illustrating a schematic configuration of the blinker light according to the second embodiment of the present invention. In FIG. 5, the same reference numerals are given to the components common to FIG. 1, and the differences will be mainly described below. The lighting control unit 20a includes a semiconductor relay (switch unit) SSR (Solid State Relay) instead of the switch SW1 of the first embodiment illustrated in FIG.

  The semiconductor relay SSR is switched on or off, and has a resistance component Rssr when it is off. In other words, in the semiconductor relay SSR, the switch SW2 and the resistance component Rssr are connected in parallel between the input / output terminals when represented by an equivalent circuit. The resistance component Rssr is, for example, several tens of kΩ, and varies depending on the type of the semiconductor relay SSR. The lighting control unit 20a supplies the first AC voltage VAC1 or the second AC voltage VAC2 to the LED lighting device 10a via the semiconductor relay SSR.

  When the semiconductor relay SSR is on, the switch SW2 is closed, and the first AC voltage VAC1 or the second AC voltage VAC2 is supplied to the LED lighting device 10a as it is via the switch SW2. When the semiconductor relay SSR is off, the switch SW2 is opened, and the first AC voltage VAC1 or the second AC voltage VAC2 is supplied to the LED lighting device 10a via the resistance component Rssr.

  Thus, the semiconductor relay SSR cannot completely cut off the first AC voltage VAC1 or the second AC voltage VAC2 even when it is off due to the presence of the resistance component Rssr. Therefore, in the LED lighting device 10 according to the first embodiment, the first LED element 11-1 may be lit even when the semiconductor relay SSR is off. In order to prevent this, the LED lighting device 10a of Example 2 is configured as follows.

  FIG. 6 is a circuit diagram of the LED lighting device 10a according to the second embodiment of the present invention. The LED lighting device 10a further includes a resistance switching unit 16 in addition to the configuration of the LED lighting device 10 of FIG. The circuit configuration other than the resistance switching unit 16 is the same as that in FIG. In order to clarify the operation of the resistance switching unit 16, FIG. 6 also shows an equivalent circuit 20a_E of the lighting control unit 20a around the semiconductor switch SSR.

  The resistance switching unit 16 includes a resistance (third resistance) R10 and a resistance (fourth resistance) R11, and switches the resistance between the first terminal T1 and the second terminal T2 based on the supplied rectified voltage Vr. One end of the resistor R10 is connected to the first terminal T1, and has a resistance lower than the resistance component Rssr of the semiconductor relay SSR. The resistor R11 has one end connected to the first terminal T1 and has a higher resistance than the resistor R10. For example, the resistance value of the resistor R11 is ten times or more the resistance value of the resistor R10. In this embodiment, the resistor R10 is about 5 kΩ, and the resistor R11 is about 200 kΩ.

  Specifically, the resistance switching unit 16 electrically connects the resistor R10 between the first terminal T1 and the second terminal T2 of the rectifier element B1 when the rectified voltage Vr is less than the determination voltage, thereby connecting the resistor R10. And electrically connected to the semiconductor relay SSR via the rectifying element B1. Therefore, when the semiconductor relay SSR is OFF, the rectified voltage Vr is stepped down by the resistance component Rssr and the resistance R10 of the semiconductor relay SSR. The value of the resistor R10 is set so that the rectified voltage Vr is less than the determination voltage when the semiconductor relay SSR is off. Therefore, when the semiconductor relay SSR is OFF, the resistor R10 is steadily electrically connected to the semiconductor relay SSR.

  The resistance switching unit 16 electrically connects a resistor R11 instead of the resistor R10 between the first terminal T1 and the second terminal T2 of the rectifying element B1 when the rectified voltage Vr is equal to or higher than the determination voltage. Thus, the resistor R11 is electrically connected to the semiconductor relay SSR via the rectifying element B1.

  In the present embodiment, the resistance switching unit 16 further includes an NPN transistor (second switching element) Q4, an NPN transistor (third switching element) Q5, and a resistor R12.

  The NPN transistor Q4 has a base (control terminal) connected to the anode (other end) of the Zener diode ZD1 included in the voltage control unit 131 via a current limiting resistor R12, and a collector ( One end) is connected, and the emitter (the other end) is connected to the second terminal T2. As a result, when the Zener diode ZD1 becomes conductive, the NPN transistor Q4 is turned on by current flowing through the resistor R12. That is, in this embodiment, the determination voltage is equal to the Zener voltage of the Zener diode ZD1.

  The NPN transistor Q5 has a base (control terminal) connected to the collector of the NPN transistor Q4, a collector (one end) connected to the other end of the resistor R10, and an emitter (other end) connected to the second terminal T2. Yes. The NPN transistor Q5 is turned off when the NPN transistor Q4 is turned on.

  Next, operation | movement of the LED lighting device 10a of a present Example is demonstrated.

(1) When the semiconductor relay SSR is off When the semiconductor relay SSR is off, the LED lighting device 10a operates so as to pass a current through the resistor R10. At this time, the first AC voltage VAC1 or the second AC voltage VAC2 is supplied via the resistance component Rssr. Therefore, the rectified voltage Vr is lower than the first AC voltage VAC1 or the second AC voltage VAC2 according to the impedance between the first terminal T1 and the second terminal T2 of the rectifying element B1.

  Immediately after the rectified voltage Vr increases from 0 V in response to the increase in the first AC voltage VAC1 or the second AC voltage VAC2, the rectified voltage Vr is less than the determination voltage, and thus the Zener diode ZD1 does not conduct. Accordingly, the NPN transistor Q4 is turned off. On the other hand, since the current flows to the base of the NPN transistor Q5 via the resistor R11 by the rectified voltage Vr, the NPN transistor Q5 is turned on. Thereby, a current flows through the resistance component Rssr of the semiconductor relay SSR in the off state, the rectifying element B1, the resistor R10, and the NPN transistor Q5. Accordingly, the first AC voltage VAC1 or the second AC voltage VAC2 is divided by the resistance component Rssr and the resistance R10 of the semiconductor relay SSR. The obtained rectified voltage Vr is stepped down below the determination voltage as described above. Therefore, even if the first AC voltage VAC1 or the second AC voltage VAC2 is maximized, no current flows through the first and second LED elements 11-1 and 11-2. The LED elements 11-1 and 11-2 are not lit.

(2) When the semiconductor relay SSR is ON At this time, the operations of the first LED element 11-1, the second LED element 11-2, the current control unit 13, and the short-circuit control unit 14 are the same as those in the first embodiment. That is, the rectified voltage Vr and the current of the first LED element 11-1 are the same as those in FIGS. Therefore, referring first to FIG. 3, the operation of the resistance switching unit 16 will be mainly described in the case where the first AC voltage VAC1 is supplied.

  When the semiconductor relay SSR is turned on, the first AC voltage VAC1 is directly supplied via the closed switch SW2, so that the rectified voltage Vr is substantially equal to the first AC voltage VAC1. From time t1 to time t2 in FIG. 3, the rectified voltage Vr increases from 0 V as the first AC voltage VAC1 increases. However, since the rectified voltage Vr is less than the determination voltage, the Zener diode ZD1 does not conduct. On the other hand, the rectified voltage Vr causes a current to flow to the base of the NPN transistor Q5 via the resistor R11, so that the NPN transistor Q5 is turned on and a current flows to the resistor R10. As the rectified voltage Vr increases, the current of the resistor R10 increases.

  When the rectified voltage Vr reaches the determination voltage at time t2, the Zener diode ZD1 becomes conductive. As a result, a current flows through the base of the NPN transistor Q4 via the Zener diode ZD1 and the resistor R12, so that the NPN transistor Q4 is turned on and the current flowing through the resistor R11 increases. Then, the base voltage of the NPN transistor Q5 decreases, and the NPN transistor Q5 is turned off. Accordingly, no current flows through the resistor R10. As described above, since the resistor R11 has a resistance value several tens of times that of the resistor R10, the current flowing through the resistor R11 is sufficiently smaller than the current flowing through the resistor R10. This state is maintained until time t7.

  From time t7 to time t8, since the rectified voltage Vr is less than the determination voltage, the Zener diode ZD1 does not conduct. Accordingly, a current flows through the resistor R10 as from the time t1 to the time t2.

  As described above, in each period from time t1 to time t2 and from time t7 to time t8, current flows through the resistor R10. From time t2 to time t7, current does not flow through the resistor R10, but current flows through the resistor R11.

  When the second AC voltage VAC2 is supplied, the same operation as described above is performed. That is, in each period from time t11 to t12 and from time t15 to t16 in FIG. 4, current flows through the resistor R10, and from time t12 to t15, current does not flow through the resistor R10, but current flows through the resistor R11.

  As described above, a current flows through the resistor R10 in a period in which the rectified voltage Vr is lower than the determination voltage. Therefore, by lowering the determination voltage, the period during which current flows through the resistor R10 can be shortened. Thereby, since the maximum value and the total amount of the current flowing through the resistor R10 and the maximum value of the voltage applied to the resistor R10 can be reduced, power loss at the resistor R10 can also be reduced.

  As described above, according to the LED lighting device 10a according to the present embodiment, when the resistance switching unit 16 has the rectified voltage Vr less than the determination voltage, the resistor R10 is connected to the semiconductor relay SSR via the rectifying element B1. They are connected electrically. In addition, when the rectified voltage Vr is equal to or higher than the determination voltage, the resistance switching unit 16 electrically connects the resistor R11 having a higher resistance than the resistor R10 to the semiconductor relay SSR via the rectifier element B1. As a result, when the semiconductor relay SSR is off, the rectified voltage Vr is stepped down by the resistance component Rssr and the resistance R10 of the semiconductor relay SSR, so that even if the resistance component Rsr of the semiconductor relay SSR exists, the first and second The LED elements 11-1 and 11-2 can be turned off.

  Further, when the semiconductor relay SSR is on, if the rectified voltage Vr becomes equal to or higher than the determination voltage, the current does not flow through the resistor R10 but flows through the high-resistance resistor R11. Accordingly, it is possible to shorten the period during which a current that does not contribute to lighting of the first and second LED elements 11-1 and 11-2 flows through the low-resistance resistor R10, thereby reducing power loss and heat generation. By reducing the amount of heat generated, the durability and reliability of the LED lighting device 10a can be improved even when the heat dissipation of the blinker light is low.

  Thus, in the LED lighting device 10a according to the present embodiment, since the power loss and the heat generation amount of the resistor R10 can be reduced, a small, low withstand voltage, and low power resistor can be used as the resistor R10. Therefore, the cost can be reduced.

  Furthermore, since the period during which current flows through the resistor R10 can be shortened, the power loss and the heat generation amount can be reduced even if the resistor R10 has a low resistance. Accordingly, even when the semiconductor relay SSR having a low resistance component Rssr is used, when the semiconductor relay SSR is turned off, the rectified voltage Vr is sufficiently lowered to light the first and second LED elements 11-1 and 11-2. You can avoid it. Accordingly, various types (manufacturers) of semiconductor relays SSR can be supported.

  The period during which current flows through the resistor R10 is determined by the rectified voltage Vr. Therefore, the period is not affected by the number of LEDs connected in series, the current values of the first and second LED elements 11-1 and 11-2, and the like.

  Furthermore, the same effect as in the first embodiment can be obtained.

  Thus, even when the lighting control unit (control panel) 20a of the blinker light already installed at a branch point of the road uses the semiconductor relay SSR, the lighting control unit 20a is used as it is, By simply replacing the incandescent bulb with the LED lighting device 10a, excellent characteristics of the LED can be obtained.

  The incandescent bulb has a characteristic that it does not light even when a voltage is applied via the resistance component Rssr when the semiconductor relay SSR is off.

  As mentioned above, although the Example of this invention was explained in full detail, a concrete structure is not limited to the said Example, A various deformation | transformation can be implemented in the range which does not deviate from the summary of this invention.

  For example, the number of LEDs constituting the first and second LED elements 11-1 and 11-2 may be different from the above example.

Further, the short-circuit control unit 14 may short-circuit both ends of the first LED element 11-1 instead of the second LED element 11-2. In this case, the current control part 13 should just control the electric current which flows into the 2nd LED element 11-2.
Further, the short-circuit switch may be composed of a P-type MOS transistor.

10, 10a LED lighting device 20, 20a lighting controller (control panel)
21 Voltage converter SW1, SW2 Switch SSR Semiconductor relay Rssr Resistance component B1 Rectifier element 11-1 First LED element 11-2 Second LED element 13 Current controller 131 Voltage controller 14 Short-circuit controller 16 Resistance switching unit Q1 N-type MOS transistor (current control transistor)
Q2 N-type MOS transistor (short-circuit switch)
Q3 NPN transistor (first switching element)
Q4 NPN transistor (second switching element)
Q5 NPN transistor (third switching element)
ZD1 Zener diode (second voltage detection element)
ZD2 Zener diode (first voltage detection element)
ZD3 Zener diode (voltage limiting element)
D1 diode (current limiting element)
R1 resistance (5th resistance)
R2 resistance (6th resistance)
R3 resistance (7th resistance)
R4 to R7 resistor R8 resistor (first resistor)
R9 resistance (second resistance)
R10 resistor (third resistor)
R11 resistor (4th resistor)
R12 Resistor IC1 Shunt regulator C1, C2 Capacitance

Claims (14)

When the amount of ambient light is greater than or equal to a predetermined reference amount of light, a first AC voltage is output. When the amount of light is lower than the reference amount of light, the second effective value is lower than the first AC voltage. An LED lighting device to which the first AC voltage or the second AC voltage is supplied from a lighting control unit that outputs an AC voltage,
A rectifying element that rectifies the first AC voltage or the second AC voltage and outputs a rectified voltage between the first terminal and the second terminal;
A first LED element having one end connected to the first terminal;
A second LED element having one end connected to the other end of the first LED element;
A current control unit that is connected between the other end of the second LED element and the second terminal and controls a current flowing through the first LED element or the second LED element;
A short-circuit control unit that short-circuits both ends of the first LED element or the second LED element when the rectified voltage is less than a predetermined short-circuit voltage,
The maximum value of the short-circuit voltage and the second AC voltage is equal to or lower than the first voltage required for both the first LED element and the second LED element to be lit, and the first The LED lighting device, wherein when one of the LED element and the second LED element is short-circuited, the other is higher than a second voltage necessary for lighting.   The LED lighting device according to claim 1, wherein the short-circuit voltage is higher than a maximum value of the second AC voltage. The short-circuit controller is
A shorting switch that is switched on or off and shorts both ends of the second LED element when on;
A first voltage detecting element having one end connected to the first terminal and conducting when the rectified voltage is equal to or higher than the short-circuit voltage;
A first resistor having one end connected to the first terminal;
A control terminal is connected to the other end of the first voltage detection element, one end is connected to the other end of the first resistor, the other end is connected to the second terminal, and the first voltage detection element is conductive. A first switching element that is turned on when
3. The LED according to claim 1, wherein the short-circuit switch is controlled to be turned on when a voltage at the other end of the first resistor is at a high level, and is controlled to be turned off when the voltage is at a low level. Lighting device. The short-circuit switch is an N-type MOS transistor,
The drain of the N-type MOS transistor is connected to a connection point between the other end of the first LED element and one end of the second LED element, and the source of the N-type MOS transistor is the other LED element. Connected to the connection point between the end and the current control unit,
The LED lighting device according to claim 3, wherein the short-circuit control unit includes a voltage limiting element that limits a voltage between a gate and a source of the N-type MOS transistor. The short circuit controller includes a current limiting element that restricts current from flowing from a connection point between the other end of the second LED element and the current controller to the short circuit controller. 4. The LED lighting device according to 4. The first voltage detecting element is a Zener diode;
The said short circuit control part has a 2nd resistance connected between the control terminal of the said 1st switching element, and the said 2nd terminal. The any one of Claims 3-5 characterized by the above-mentioned. LED lighting device. A resistance switching unit that includes a third resistor and a fourth resistor, and switches a resistance between the first terminal and the second terminal based on the supplied rectified voltage;
The lighting control unit supplies the first AC voltage or the second AC voltage to the rectifying element via a switch unit that is switched on or off and has a resistance component when off. When the rectified voltage is less than the determination voltage, the unit connects the third resistor between the first terminal and the second terminal, thereby electrically connecting the third resistor to the switch unit via the rectifier element. When the rectified voltage is equal to or higher than the determination voltage, the fourth resistor having a higher resistance than the third resistor is connected between the first terminal and the second terminal instead of the third resistor, The LED lighting device according to claim 1, wherein the fourth resistor is thereby electrically connected to the switch unit via the rectifying element. The LED lighting device according to claim 7, wherein when the switch unit is off, the rectified voltage is stepped down below the determination voltage by the resistance component of the switch unit and the third resistor. The LED lighting device according to claim 7 or 8, wherein the third resistor has a lower resistance than the resistance component of the switch unit. The current controller is
A current control transistor having one end connected to the other end of the second LED element;
A fifth resistor connected between the other end of the current control transistor and the second terminal;
The voltage control part which controls the voltage of the control terminal of the said current control transistor so that the voltage of the other end of the said current control transistor may become constant, The any one of Claim 7 to 9 characterized by the above-mentioned. LED lighting device according to. The voltage controller is
A second voltage detecting element having one end connected to the first terminal and conducting when the rectified voltage is equal to or higher than the determination voltage; and the determination voltage is less than the second voltage;
A sixth resistor having one end connected to the other end of the second voltage detection element;
A seventh resistor connected between the other end of the sixth resistor and the second terminal;
The cathode is connected to the other end of the sixth resistor and the control terminal of the current control transistor , the anode is connected to the second terminal, and a reference voltage based on the voltage at the other end of the current control transistor is supplied to the reference terminal. The LED lighting device according to claim 10, further comprising: a shunt regulator that decreases the cathode voltage when the reference voltage increases and increases the cathode voltage when the reference voltage decreases. The resistance switching unit
A control terminal is connected to the other end of the second voltage detection element of the voltage control unit, and one end and the other end are connected between the fourth resistor and the second terminal, and the second voltage detection element A second switching element that is turned on when is conducted;
A control terminal is connected to the one end of the second switching element, one end and the other end are connected between the third resistor and the second terminal, and the second switching element is turned off when the second switching element is turned on. The LED lighting device according to claim 11, further comprising: The LED lighting device according to any one of claims 1 to 12, wherein each of the first LED element and the second LED element includes a plurality of LEDs connected in series. . The first LED lighting device according to any one of claims 1 to 13,
The second LED lighting device according to any one of claims 1 to 13,
When the amount of ambient light is greater than or equal to a predetermined reference amount of light, the first alternating voltage is alternately supplied to the first and second LED lighting devices, while when the amount of light is lower than the reference amount of light, A lighting control unit that alternately supplies a second AC voltage having an effective value lower than that of the first AC voltage to the first and second LED lighting devices.

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